I have just bought an H4D-50 and 35-90mm lens from a dealer in Portugal. I've been test shooting a bottle of whisky today, and started to notice a mist in the centre of the frame. Upon examining the lens I see that there is a 5mm diameter area of condensation on the back element. The earlier shots aren't affected, so it has developed during the day. I didn't have the heating on and the studio is very cold. How long will the condensation take to clear, and how is it best avoided in future ? Also is this a problem with these massive Hassy lenses? Can't say I've ever seen it happen on my Canons.